1. Field of Invention
The present disclosure relates to antennas for transmitting/receiving electromagnetic field (EMF) signals.
2. Background
Rubee and RFID are two asset-identification technologies used to identify and track objects using tags embedded in or otherwise attached to the objects. Both of these technologies use antennas to wirelessly communicate with the tags and receive identification or other information therefrom. The electrical and physical configuration of the antennas is important since such configuration can affect the range and effectiveness with which the antennas can communicate with the tags.
Typically, antennas used by asset-identification systems use a single coil of conductive wire or multiple coils of conductive wire connected in series. The coils typically include a small number of turns to provide a desired inductance. Unfortunately, the small number of turns can significantly limit the antennas' ability to receive data. Most systems overcome this problem by transmitting more power through the antenna. This provides the tag more power to transmit its signal back to the antenna, and thus less sensitivity by the antenna to read the signal.
Another way to improve reception is by using an additional antenna. Unfortunately, an additional antenna requires space and can therefore significantly increase overall package size. For this reason, most systems use a single high power antenna for both transmitting and receiving data. With such antennas, the transmitting range is significantly larger than the reading range, creating an undesirable imbalance.
In view of the foregoing, what are needed are improved antennas for use in wireless asset-identification systems, such as Rubee/RFID asset-identification systems. Ideally, such antennas will be effective at both transmitting power and receiving data. Further needed are antennas with an improved receiving range compared to conventional antennas.